package Servlet;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

@WebServlet(name = "upLoadServlet")
public class upLoadServlet extends HttpServlet {
    private  static  final  long serialVersionUID=1L;
    //上传文件储存目录
    // 上传文件存储目录
    private static final String UPLOAD_DIRECTORY = "upload";

    // 上传配置
    private static final int MEMORY_THRESHOLD   = 1024 * 1024 * 3;  // 3MB
    private static final int MAX_FILE_SIZE      = 1024 * 1024 * 40; // 40MB
    private static final int MAX_REQUEST_SIZE   = 1024 * 1024 * 50; // 50MB

    /**
     * 上传数据及保存文件
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    if (!ServletFileUpload.isMultipartContent(request)){
        // 如果不是则停止
        PrintWriter writer = response.getWriter();
        writer.println("Error: 表单必须包含 enctype=multipart/form-data");
        writer.flush();
        return;
    }
    // 配置上传参数
    DiskFileItemFactory factory = new DiskFileItemFactory();

    // 设置内存临界值 - 超过后将产生临时文件并存储于临时目录中
    factory.setSizeThreshold(MEMORY_THRESHOLD);
    // 设置临时存储目录
    factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
    ServletFileUpload upload=new ServletFileUpload(factory);

    // 设置最大文件上传值
    upload.setFileSizeMax(MAX_FILE_SIZE);


    // 设置最大请求值 (包含文件和表单数据)
    upload.setSizeMax(MAX_REQUEST_SIZE);

    // 中文处理
    upload.setHeaderEncoding("UTF-8");


    // 构造临时路径来存储上传的文件
    // 这个路径相对当前应用的目录
    String uploadPath = getServletContext().getRealPath("./") + File.separator + UPLOAD_DIRECTORY;

    // 如果目录不存在则创建
    File uploadDir = new File(uploadPath);
    if (!uploadDir.exists()) {
        uploadDir.mkdir();
    }
        try {
            // 解析请求的内容提取文件数据
            @SuppressWarnings("unchecked")
            List<FileItem> formItems = upload.parseRequest(request);

            if (formItems != null && formItems.size() > 0) {
                // 迭代表单数据
                for (FileItem item : formItems) {
                    // 处理不在表单中的字段
                    if (!item.isFormField()) {
                        String fileName = new File(item.getName()).getName();
                        System.out.println(fileName);
                        String filePath = uploadPath + File.separator + fileName;
                        File storeFile = new File(filePath);
                        // 在控制台输出文件的上传路径
                        System.out.println(filePath);
                        // 保存文件到硬盘
                        item.write(storeFile);
                        request.setAttribute("message",
                                "文件上传成功!");
                    }
                }
            }
        } catch (Exception ex) {
            request.setAttribute("message",
                    "错误信息: " + ex.getMessage());
        }
        getServletContext().getRequestDispatcher("/message.jsp").forward(request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }
}
